As I stated in an earlier post...my 1992 VFR400 wouldnt rev past 9k,
I was messing with it today,,,and it will rev just fine if it is sitting still,
it is only when I am moving that it won't rev up....so I am thinking a fuel issue,
can anyone give me any idea of what the jet sizes should be...at least for a starting point,
it has a Tyga full system...and I just installed a foam air filter in the air box....
it is a race only bike....
this is my first attempt at working on a carbureated bike,,so please excuse my ignorance...
if more info is needed to get me a starting point let me know and I willl try to help...

d

It's the filter mate. They need massive jetting changes to suit a higher flow filter.

Replace it with a standard one and a standard airbox and it will pull like a 12 year old.

For your foam filter you'll need between 128-132 main jets, a dyno is needed because of the variable flow rates of these filters.